Automated media storage libraries are known for providing cost effective access to large quantities of stored media. Generally, media storage libraries include a large number of storage slots on which are stored portable data storage media. The typical portable data storage media is a tape cartridge, an optical cartridge, a disk cartridge, electronic storage media, and the like. By electronic storage media, Applicants mean a device such as a PROM, EPROM, EEPROM, Flash PROM, compactflash (compactflash is a registered trademark of Sandisk corporation), smartmedia (smartmedia is a registered trademark of Kabushiki Kaisha Toshiba DBA Toshiba Corporation), and the like.
One (or more) accessors typically accesses the data storage media from the storage slots and delivers the accessed media to a data storage device for reading and/or writing data on the accessed media. Suitable electronics operate the accessor(s) and operate the data storage device(s) to provide information to, and/or to receive information from, an attached on-line host computer system.
In a conventional automated media storage library, the storage slots are arranged in a planar orthogonal arrangement forming a “wall” of storage slots for holding data storage media. The plane may be a flat plane, or may be a cylindrical plane. To double the storage capacity, two “walls” of storage slots may be provided on either side of the accessor.
A number of different companies manufacture automated media storage libraries today, each model displaying various different features. One example is the IBM TOTALSTORAGE 3494 ENTERPRISE TAPE LIBRARY. Some of the automated media storage libraries have dual or multiple accessors to provide a level of redundancy and to enhance performance.
Prior art data storage and retrieval systems include a single operator station which allows a user to manage the operation and status of the library. Applicants' data storage and retrieval system includes at least one local operator station. In addition, however, Applicants' data storage and retrieval system is capable of communicating with one or more remote operator stations. Applicants' invention further includes a method whereby a remote user, using a remote operator station, can change the IP address of the data storage and retrieval system.
In the most widely installed level of the Internet Protocol (“IP”) today, an IP address is a 32-bit number that identifies each sender or receiver of information that is sent in packets across the Internet. When a user requests an HTML page, the Internet Protocol part of TCP/IP includes the user's IP address in the message (actually, in each of the packets if more than one is required) and sends it to the IP address that is obtained by looking up the domain name in the Uniform Resource Locator (“URL”) requested. At the other end, the recipient can see the IP address of the Web page requester and can respond by sending another message using the IP address it received.
An IP address has two parts: the identifier of a particular network on the Internet and an identifier of the particular device (which can be a server or a workstation) within that network. On the Internet itself—that is, between the router that moves packets from one point to another along the route—only the network part of the address is used.
In addition to the network address or number, information is needed about which specific machine or host in a network is sending or receiving a message. So the IP address needs both the unique network number and a host number, which is unique within the network. Part of the local address can identify a subnetwork or subnet address, which makes it easier for a network that is divided into several physical subnetworks, for example, several different local area networks, to handle many devices.
Because networks vary in size, there are four different address formats or classes that have historically been used:                Class A addresses are for large networks with many devices.        Class B addresses are for medium-sized networks.        Class C addresses are for small networks (fewer than 256 devices).        Class D addresses are multicast addresses.The first few bits of each IP address indicate which of the address class formats it is using. Such address structures comprise:        
Class A0Network (7 bits)Local address (24 bits)Class B10Network (14 bits)Local address (16 bits)Class C110Network (21 bits)Local address (8 bits)Class D1110Multicast address (28 bits)
The IP address is usually expressed as four decimal numbers, each representing eight bits, separated by periods. This is sometimes known as the dot address and, more technically, as dotted quad notation. For Class A IP addresses, the numbers would represent “network.local.local.local”; for a Class C IP address, they would represent “network.network.network.local”. The number version of the IP address can (and usually is) represented by a name or series of names called the domain name.
Internet Protocol Version 6, expands the size of the IP address to 128 bits, which can accommodate growth in the number of network addresses. For hosts still using IPv4, the use of subnets in the host or local part of the IP address will help reduce new applications for network numbers. In addition, many sites using IPv4 Internet have mitigated the Class C network address limitation by using the Classless Inter-Domain Routing (“CIDR”) scheme for address notation.
The machine or physical address used within a local area network may differ from the Internet's IP address. The most typical example is the 48-bit Ethernet address. TCP/IP includes a facility called the Address Resolution Protocol that allows use of a table that maps IP addresses to physical addresses. The table is known as the ARP cache.